The present invention relates to canard type aircraft. More specifically, the present invention relates to aircraft having their steering mechanism arranged near the front end and integrated into the surface of the wing means, whereby the steering mechanism, or rather, the rudder elements thereof, are tiltable about an axis which forms an acute angle with the longitudinal axis of the aircraft fuselage or body. Such an aircraft is disclosed, for example, in U.S. Pat. No. 3,104,079. The aircraft suggested in said U.S. Pat. No. is characterized in that the tilting axis of the forward rudder mechanism extends outside the surface of the wing means or the tilting axis is located contiguous relative to the wing means, whereby the integration of the steering mechanism and the wing means is more of an aggregating nature rather than a true combination, the latter providing a synergistic result, whereas the former merely provides the sum of the individual effects.
In order to improve the flying characteristics of such aircraft, especially modern fighter aircraft, the wings thereof have been provided with smooth outlines or so-called sheers or strakes. The advantageous effect of such strakes resides especially in the fact that the excursion of the aerodynamic center of the aircraft is reduced and that in the range of subsonic speeds the start of the so-called buffeting has been shifted into higher speed ranges. These aerodynamic advantages, however, are achieved by additional weight. It is thus desirable, to make a more efficient use of the efforts connected with the provision of said sheers or strakes in order to improve the flying characteristics of such aircraft. Stated differently, it is desirable to make the so-called "strakes" movable and also reduce the weight thereof.
Examples of tiltable and slidable strakes are known which facilitate the trim of the aircraft and which are intended to influence the excursion of the aerodynamic center as a function of the flying speed. However, all of the prior art suggestions have not brought an additional benefit or efficiency worth mentioning in spite of having a good aerodynamic effect. The necessary structural input, so to speak, requires such a high weight that any aerodynamic benefit is again negated by such increased weight.
A further disadvantage of prior art devices is seen in that the sealing of the movable sheers or strakes relative to the fuselage, has frequently caused substantial difficulties. Besides, due to the large adjustment or displacement distances or tilting angles, rather small adjustment speeds may be accomplished. Thus, the prior art devices are not suitable for use as steering means.